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Seven years of IASI ozone retrievals from FORLI: validation with independent total column and vertical profile measurements

Boynard, A. and Hurtmans, D. and Koukouli, M. and Goutail, F. and Bureau, J. and Safieddine, S. and Lerot, Christophe and Hadji-Lazaro, J. and Wespes, C. and Pommereau, J. P. and Pazmino, Andrea and Zyrichidou, I. and Balis, D. and Barbe, A. and Mikhailenko, S. and Loyola, Diego and Valks, Pieter and Van Roozendael, Michel and Coheur, P.-F. and Clerbaux, C. (2016) Seven years of IASI ozone retrievals from FORLI: validation with independent total column and vertical profile measurements. Atmospheric Measurement Techniques (AMT), 9 (9), pp. 4327-4353. Copernicus Publications. DOI: 10.5194/amt-9-4327-2016 ISSN 1867-1381

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Official URL: http://www.atmos-meas-tech.net/9/4327/2016/

Abstract

This paper presents an extensive intercomparison and validation for the ozone (O3) product measured by the two Infrared Atmospheric Sounding Interferometers (IASIs) launched on board the MetOp-A and MetOp-B satellites in 2006 and in 2012 respectively. IASI O3 total columns and vertical profiles obtained from Fast Optimal Retrievals on Layers for IASI (FORLI) v20140922 software (running up until recently) are validated against independent observations during the period 2008–2014 on a global scale. On average for the period 2013–2014, IASI-A and IASI-B total ozone columns (TOCs) retrieved using FORLI are consistent, with IASI-B providing slightly lower values with a global difference of only 0.2 ± 0.8 %. The comparison between IASI-A and IASI-B O3 vertical profiles shows differences within ± 2 % over the entire altitude range. Global validation results for 7 years of IASI TOCs from FORLI against the Global Ozone Monitoring Experiment-2 (GOME-2) launched on board MetOp-A and Brewer–Dobson data show that, on average, IASI overestimates the ultraviolet (UV) data by 5–6 % with the largest differences found in the southern high latitudes. The comparison with UV–visible SAOZ (Système d'Analyse par Observation Zénithale) measurements shows a mean bias between IASI and SAOZ TOCs of 2–4 % in the midlatitudes and tropics and 7 % at the polar circle. Part of the discrepancies found at high latitudes can be attributed to the limited information content in the observations due to low brightness temperatures. The comparison with ozonesonde vertical profiles (limited to 30 km) shows that on average IASI with FORLI processing underestimates O3 by  ∼  5–15 % in the troposphere while it overestimates O3 by ∼  10–40 % in the stratosphere, depending on the latitude. The largest relative differences are found in the tropical tropopause region; this can be explained by the low O3 amounts leading to large relative errors. In this study, we also evaluate an updated version of FORLI-O3 retrieval software (v20151001), using look-up tables recalculated to cover a larger spectral range using the latest HITRAN spectroscopic database (HITRAN 2012) and implementing numerical corrections. The assessment of the new O3 product with the same set of observations as that used for the validation exercise shows a correction of ∼  4 % for the TOC positive bias when compared to the UV ground-based and satellite observations, bringing the overall global comparison to ∼  1–2 % on average. This improvement is mainly associated with a decrease in the retrieved O3 concentration in the middle stratosphere (above 30 hPa/25 km) as shown by the comparison with ozonesonde data.

Item URL in elib:https://elib.dlr.de/105987/
Document Type:Article
Title:Seven years of IASI ozone retrievals from FORLI: validation with independent total column and vertical profile measurements
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Boynard, A.LATMOSUNSPECIFIED
Hurtmans, D.Univ. Libre de Bruxelles, Brussels, BUNSPECIFIED
Koukouli, M.AUTHUNSPECIFIED
Goutail, F.LATMOS, CNRS, FranceUNSPECIFIED
Bureau, J.LATMOSUNSPECIFIED
Safieddine, S.LATMOSUNSPECIFIED
Lerot, ChristopheBIRA-IASBUNSPECIFIED
Hadji-Lazaro, J.LATMOSUNSPECIFIED
Wespes, C.Catherine.Wespes (at) ulb.ac.beUNSPECIFIED
Pommereau, J. P.LATMOSUNSPECIFIED
Pazmino, AndreaLATMOSUNSPECIFIED
Zyrichidou, I.AUTHUNSPECIFIED
Balis, D.AUTHUNSPECIFIED
Barbe, A.Universite de Reims-Champagne-ArdenneUNSPECIFIED
Mikhailenko, S.Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, Russian Academy of Sciences, Tomsk, RussiaUNSPECIFIED
Loyola, DiegoDLR-IMFUNSPECIFIED
Valks, PieterDLR-IMFUNSPECIFIED
Van Roozendael, MichelBIRA-IASBUNSPECIFIED
Coheur, P.-F.Univ. Libre de Bruxelles, Brussels, BUNSPECIFIED
Clerbaux, C.LATMOSUNSPECIFIED
Date:5 September 2016
Journal or Publication Title:Atmospheric Measurement Techniques (AMT)
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:9
DOI :10.5194/amt-9-4327-2016
Page Range:pp. 4327-4353
Editors:
EditorsEmail
Wagner, Thomasthomas.wagner@mpic.de
Publisher:Copernicus Publications
ISSN:1867-1381
Status:Published
Keywords:ozone, satellite, IASI, validation
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Erdbeobachtung
DLR - Research theme (Project):R - Vorhaben Ozon-SAF (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Remote Sensing Technology Institute > Atmospheric Processors
Deposited By: Valks, Dr. Pieter
Deposited On:07 Sep 2016 10:32
Last Modified:08 Mar 2018 18:10

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